Dna-templated Syntheses, Characterizations And Luminescent Property Studies Of Asymmetric Schiff-base Complexes

According to the principle of Watson-Crick base pairing, a series of asymmetric Schiff base complex [Zn2Lnen Cl2] are synthesized step to step via DNA Template,(L1=D3-4M-D4-4M, L2=D3-4M-D4-4H, L3=D3-4M-D4-4T, L4=D3-4M-D4-4Cl, D3=C182H236O108N71P18、D4=C182H239O111N66P18, 4M=4-Methyl-2,6-diformylphenol, 4H=2-hydroxyisophthalaldehyde, 4T=4-tert-Butyl-2,6-diformylphenol, 4Cl=5-chloro-2-hydroxyisophthalaldehyde, en=ethanediamine). The products are purified and separated by centrifugation ultrafiltration, HPLC and gel-electrophoresis method, and characteried by UV- vis spectra, mass spectra and Circular dichroism Spectroscopy. The fluorescence studies at room temperature indicate that the asymmetric Schiff-base complexs emit strong fluorescence at about 490 nm, which can be probably assigned to π*- π or π*- n electron transitions. Furthermore, three different asymmetric Schiff-base compounds Ln(n=2, 3, 4) can act as probes, which have preferable recognition for Cd2+, with the minimum detectable density 3.6×10-5 mol/L. The p H- study shows the most sensitive detection p H value to Cd2 + is 9.